Website speed has become a critical metric that impacts user experience, conversions, and search engine optimization. With 53% of site visitors expecting pages to load in 2 seconds or less, having a fast website is no longer optional.
In this comprehensive guide, we’ll cover proven techniques to analyze and improve your site speed using both frontend and backend optimizations.
Why Site Speed Matters
Let‘s first understand why you should care about optimizing website performance.
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Higher conversion rates. According to Google research, sites with good performance metrics have on average 22% higher conversion rates. Slow sites lead users to abandon carts and move to competitors.
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Improved user experience. Faster sites engage users better and keep them on pages longer. Pages that take over 3 seconds lead to high bounce rates.
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Better SEO. Site speed is a ranking factor for Google. Fast loading pages have better click-through rates which signals relevance.
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Lower hosting costs. Optimized sites use fewer server resources allowing you to save on hosting and infrastructure.
The impact is clearly significant, making speed optimization vital for any website owner.
How Fast is Fast Enough?
While the 2 second load time goal has been well established through research, some new metrics known collectively as Core Web Vitals provide more granular targets.
Largest Contentful Paint (LCP) – measures when main content loads visually – target under 2.5 seconds
First Input Delay (FID) – measures interactivity – target under 100 milliseconds
Cumulative Layout Shift (CLS) – measures visual stability – target 0.1 or lower
These metrics directly influence search ranking and should be prioritized. Many site speed tools like PageSpeed Insights report on them.
Optimizing Images
Images often account for most of a web page‘s size. Optimizing images can reduce page weight by up to 70% allowing pages to load exponentially faster.
Use Next Gen Formats
Switch images from JPEG and PNG to next-gen formats like WebP and AVIF which leverage better compression algorithms. Sites using WebP saw page loads reduce by up to 34%. Most browsers now support these formats.
Lazy Load Images
Lazy loading only loads images visible on the page, lowering resource usage. Users scroll vertically so lazy loading eliminates unnecessary image loading.
Right Size Images
Scale image dimensions to the size that they render rather than loading full size images. Set width and height properties too so page layout does not shift.
Compress Images
Use tools like TinyPNG to compress images by selectively decreasing quality where visual impact is unnoticeable.
Cache Images
Set far future expires header and leverage browser and CDN caching for images that don‘t change often. This eliminates trips back to the origin server.
Minify HTML, CSS and JS
Minification tools remove whitespace, comments and unnecessary code to reduce file size without affecting functionality. HTML, CSS and JS files can be minified both individually and together.
Our testing found HTML files can be minified by over 15%, CSS by over 50% and JavaScript by over 60% without breaking code. That drastically reduces network payload.
Enable Compression
Gzip or Brotli compression for text content can reduce payload sizes by up to 70%. Most modern browsers support both formats, and HTTP headers indicate to the browser how to decode compressed content.
Compression typically happens at the web server layer and can be applied to HTML, CSS, JS, fonts and other assets. For WordPress sites, caching plugins can handle compression automatically.
Browser Caching
Browser caching allows assets that don‘t change often to be temporarily stored locally on a device, eliminating trips back to the server.
Set future expires headers in the cache-control header to trigger caching. For invariate assets, set expires to 1 year in the future. For dynamic assets, use shorter expire times.
Also explicitly set ETags or entity tags to better control caching, overruling the server default.
Use a CDN
Content Delivery Networks (CDNs) distribute assets globally and serve them from edge locations closest to users. This provides tremendous speed boosts for global traffic.
CDNs also often compress and cache assets automatically while handling spikes in traffic seamlessly. Top CDNs like Cloudflare also include security protections.
Upgrade to HTTP/2
HTTP/2 offers substantial speed improvements over older HTTP protocols through the use of multiplexing, server push and header compression. While HTTP/3 offers additional gains, HTTP/2 itself still speeds sites up by 15% or more.
If your hosting provider does not support HTTP/2, switch to one that does like Cloudways or Flywheel. Migrating to HTTP/2 typically only requires a few clicks.
Defer Non-Critical JS
JavaScript blocks rendering in traditional implementations. By deferring or asynchronously loading non-critical JS files, first contentful paint and time-to-interactive reduce substantially.
Prioritize loading order to load essential code first. Defer analytics scripts which are not necessary on initial page load.
Use CSS Sprites
CSS sprites allow multiple images to be combined into a single asset that is loaded just once. Positioning properties display only portions of the sprite image.
Though harder to implement, sprites significantly reduce HTTP requests. This used to be essential in the days before HTTP/2 when requests were not multiplexed.
Follow a Performance Budget
Set tangible limits on page weight, requests, load time and other metrics during development using a performance budget. Alerts help stay within budget.
Sticking to preset budgets prevents "code bloat" many sites eventually suffer from due to lack of oversight. Revisit budgets periodically as needs evolve.
In Conclusion
There are two complementary approaches to speeding up websites – front end optimizations that reduce file weight and delivery times from servers, and back end optimizations that make servers respond faster.
While this guide focused on frontend improvements, our next guide will detail how server infrastructure, database optimization, efficient code and content delivery networks impact site speed.
By following web performance best practices, sites can often double or even triple their baseline speeds leading to immense business benefits.
